In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data
small rectangle
length = 4
perimeter = 28
big rectangle
length = 12
perimeter = ?
Step 02:
small rectangle
perimeter = 2l + 2w
28 = 2 * 4 + 2 w
28 - 8 = 2w
20 / 2 = w
10 = w
big rectangle
[tex]\frac{4}{12}\text{ = }\frac{10}{w}[/tex]4 w = 10 * 12
w = 120 / 4 = 30
Perimeter = 2*12 + 2*30
= 24 + 60 = 84
The answer is:
The perimeter of the big rectangle is 84.
